Apparatus for dewatering a bituminous emulsion

ABSTRACT

THE METHOD OF THE PRESENT INVENTION COMPRISES FLOWING A BITUMINOUS EMULSION OR FROTH BETWEEN TWO CLOSELY AND UNIFORMLY SPACED SURFACES WHILE PERIODICALLY VARYING THE DISTANCE BETWEEN THE TWO SURFACES, THUS IMPARTING SHEARING ENERGY TO THE EMULSION AND THEREBY COALESCING THE WATER CONTAINED IN THE EMULSION. THE DISTANCE BETWEEN THE SURFACES IS PREFERABLY VARIED BY VIBRATING AT LEAST ONE OF THE SURFACES RELATIVE TO THE OTHER IN A DIRECTION PERPENDICULAR TO THE PLANES OF THE SURFACES. THE APPARATUS COMPRISES A LONGITUDINALLY EXTENDING AND LONGITUDINALLY MOVABLE FLAT SURFACE, A LONGITUDINALLY EXTENDING FLAT SURFACE MOUNTED IN OPPOSING UNIFORM SPACED RELATIONSHIP TO SAID MOVABLE SURFACE, MEANS FOR FEEDING THE EMULSION BETWEEN THE TWO SURFACES AND MEANS FOR PERIODICALLY VARYING THE GAP OR DISTANCE BETWEEN THE SURFACES THEREBY IMPARTING A SHEARING ENERGY TO THE EMULSION. MORE PARTICULARLY THE APPARATUS COMPRISES AN UPPER PULLEY ROTATABLY MOUNTED ON A HORIZONTAL AXIS AT AN ACUTE ANGLE ABOVE THE LOWER PULLEY AND SPACED THEREFROM, A CONTINUOUS ENDLESS BELT MOUNTED ON AND BETWEEN THE PULLEYS AND DRIVEN BY ONE OF THE PULLEYS, A FLAT PLATE MOUNTED IN VARIABLE SPACED RELATIONSHIP TO THE ENDLESS BELT, A MEANS FOR FEEDING EMULSIONOR FROTH INTO THE SPACE BETWEEN THE PLATE AND THE BELT, AND A MEANS FOR PERIODICIALLY VARYING THE SPACE BETWEEN THE PLATE AND THE BELT WHEREBY THE PLATE AND THE MOVING BELT OPPOSITE THE PLATE APPLY CONTROLLED SHEARING AND WATER COALESCING ACTION TO THE EMULSION.

DEWATERING Fell 1971 L. M. o. CYMBALISTY 3,562,379

APPARATUS FOR DEWATERING A BITUMINOUS EMULSION Filed June 1'7, 1968 LLE K70 68 /LEMULSION 1 WTER INVENTOR LUBOMYR M.O- CYMBAJJSTY ATTORNEY 3,562,179 APPARATUS FOR nnwnrnnnso A nirnMrNoUs EMULSION I lllubomyr M. 0. Cymbalisty, Edmonton, Alberta, Canada,

ILLS. Cl. 252360 6 Claims ABSTRACT OF THE DISCLOSURE The method of the present invention comprises flowing a bituminous emulsion or froth between two closely and uniformly spaced surfaces while periodically varying the distance between the two surfaces, thus imparting shearing energy to the emulsion and thereby coalescing the water contained in the emulsion. The distance between the surfaces is preferably varied by vibrating at least one of the surfaces relative to the other in a direction perpendicular to the planes of the surfaces. The apparatus comprises a longitudinally extending and lon gitudinally movable flat surface, a longitudinally extending flat surface mounted in opposing uniform spaced relationship to said movable surface, means for feeding the emulsion between the two surfaces and means for periodically varying the gap or distance between the surfaces thereby imparting a shearing energy to the emulsion. More particularly the apparatus comprises an upper pulley rotatably mounted on a horizontal axis at an acute angle above the lower pulley and spaced therefrom, a continuous endless belt mounted on and between the pulleys and driven by one of the pulleys, a flat plate mounted in variable spaced relationship to the endless belt, a means for feeding emulsion or froth into the space between the plate and the belt, and a means for periodically varying the space between the plate and the belt whereby the plate and the moving belt opposite the plate apply controlled shearing and water coalescing action to the emulsion.

BACKGROUND OF THE INVENTION The invention relates to a process and apparatus for removing a substantial part of the water content of a hydrocarbon material emulsion. More particularly the apparatus is directed to removing a substantial quantity of water contained in a bituminous emulsion obtained from the hot water separation of bitumen from a slurry of water and tar sand.

Large deposits of bituminous sand are found in various localities throughout the world. The term bituminous sand is used herein to include those materials commonly referred to as oil sand, tar sand and the like. One of the most extensive deposits of bituminous sand occurs, for instance, in the Athabasca District of the Province of Alberta, Canada.

Typically, these sands contain from about 6% to about Cir 3,552,179 Patented Feb. 9, 1971 20% of bitumen (also referred to herein as oil), from about 1% to about 10% of water, and from about to about 90% of mineral solids. The specific gravity of the bitumen varies from about 1.0 to about 1.05 and the bitumen has an API gravity of about 8.0 degrees. This value for specific gravity as well as that of the specific gravity of any other material given herein is taken at 60 P. All percentage values are on a weight basis unless otherwise specified.

The major portion, by weight, of the mineral solids in bituminous sand is quartz sand having a particle size greater than about 45 microns and less than 2,000 microns. The term mineral is used herein to describe material of inorganic origin such as sand, clay and the like as distinguished from material of organic origin such as coke. For the most part, the remaining mineral solid material has a particle size of less than about 45 microns. This smaller-size mineral solid material is referred to as fines. The fines contain clay and silt including some very small particles of sand. The fines content typically varies from about 10% to about 30% by weight of the total solid mineral content of bituminous sand. However, it is not uncommon for the ingredients of bituminous sand to vary from the abovementioned concentra trons.

Various methods are known for separating bitumen from bituminous sand. Some of these methods involve the use of water for preparing a slurry at a temperature above F. Most of the coarse sand and portions of the fines are separated from the slurry by various means, such as settling, to recover an emulsion, or froth, which contains some of the fines and quantities of coarse sand. Such an emulsion or froth is referred to herein as a bituminous emulsion.

Although the bituminous emulsion employed as the feedstock of this invention is not dependent on any particular technique in the water extraction of bituminous said, one well-known method for preparing such emulsions is often referred to as the hot water process. In the hot-water process, the bituminous sand is slurried with steam and hot water at about 180 F. and the pulp is then agitated with a stream of circulating hot water and carried to a separation cell maintained at an elevated temperature of about 180 F. In the separation cell, entrained air causes the bitumen to rise to the top of the cell in the form of an emulsion containing air, bitumen, water and mineral solids. The mineral solids are extremely difficult to separate from the bitumen and, unless the emulsion is further treated, it will generally contain at least 5% of mineral solids. This bituminous emulsion or froth can be subjected to water washing to effect a partial reduction in solids.

A bituminous emulsion, such as that obtained by the above-described procedures, often contains from about 10% to about 60% water, 5% to about 20% of mineral solids and from about 30% to about bitumen. Usually, however, the bituminous emulsion or froth will contain, by weight, from about 25% to about 50% water, about 5% to about 12% mineral solids and about 35% to about 70% bitumen.

Separation of water and mineral solids from the bituminous emulsion is necessary for most ultimate uses of 3 the bitumen. However, the separation of water and mineral solids from the emulsion is difficult.

A number of methods have been proposed for breaking bituminous emulsions and recovering the bitumen. However, these generally suffer from various shortcomings such as incomplete separation or high cost. One such method involves gravity settling of solids and water after dilution with light hydrocarbon solvent.

SUMMARY OF THE INVENTION I have therefore invented an improved dewatering method and apparatus for separating water from hydrocarbon material in bituminous emulsion or froth. Briefly, the method of the present invention comprises flowing a bituminous emulsion or froth between two closely and uniformly spaced surfaces while periodically varying the distance between the two surfaces, thus imparting shearing energy to the emulsion and thereby coalescing the water contained in the emulsion. The distance between the surfaces is preferably varied by vibrating at least one of the surfaces relative to the other in a direction perpendicular to the plane of the surfaces. The apparatus comprises a longitudinally extending and longitudinally movable flat surface, a longitudinally extending flat surface mounted in opposing uniform spaced relationship to said movable surface, means for feeding the emulsion between the two surfaces and means for periodically varying the gap or distance between the sur faces thereby imparting a shearing energy to the emulsion. More particularly the apparatus comprises an upper pulley rotatably mounted on a horizontal axis at an acute angle above the lower pulley and spaced therefrom, a continuous endless belt mounted on and between the pulleys and driven by one of the pulleys, a flat plate mounted in variable spaced relationship to the endless belt, a means for feeding emulsion or froth into the space between the plate and the belt, and a means for periodically varying the space between the plate and the belt whereby the plate and the moving belt opposite the plate apply controlled shearing and water coalescing action to the emulsion.

Accordingly, it is an object of this invention to provide an improved apparatus for dewatering an oil-water emulsion.

Another object of this invention is to provide an apparatus for continuously and efficiently separating hydrocarbon material from water in an emulsion.

Other objects and advantages will be apparent to those skilled in the art from the description of the drawings and the preferred embodiments which follows.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a preferred form of the dewatering apparatus for applying the method of this invention; and

FIG. 2 is a schematic drawing of another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS More generally, the method of the present invention comprises flowing a bituminous emulsion or froth between two closely and uniformly spaced surfaces while periodically varying the distance between the two surfaces, thus imparting shearing energy to the emulsion and thereby coalescing water contained therein. The distance between the surfaces can conveniently be varied by vibrating at least one of the surfaces relative to the other in a direction perpendicular to the plane of the surfaces. Such vibration may be of any suitable amplitude and frequency but frequencies between about 100 and about 1,000 cycles per minute and amplitudes between about Mr and about /2 the normal distance between the surfaces have been found most suitable. The

normal distance or gap between the surfaces can be varied from about /a inch to about /2 inch and is preferably between about 7 inch and A inch.

By periodically varying the distance between two surfaces between which emulsion is flowing in accordance with the invention, the emulsion is periodically squeezed and shearing forces are applied thereto to effect coalescence of water in the emulsion. Sufficient shearing energy is preferably imparted to coalesce a desired amount of water from the emulsion and it has been found that maximum benefit may be obtained if shearing energy is imparted to the emulsion in amounts between about 500 and about 4,000 ft.-lbs. of energy per lb. of bitumen in the emulsion. Such energy is preferably applied at rates between about 0.01 and 0.1 horsepower per pound of bitumen. The use of additional amounts of shearing energy usually produces very little additional benefit for the additional expense while the use of less than about 500 ft.-lbs. of shearing energy per lb. of bitumen usually does not coalesce enough water to reduce the water content of the emulsion sufficiently below that which could be obtained by more conventional means such as settling.

In practicing this invention, it has also been found that the temperature at which the coalescence takes place has a significant effect upon the process. Temperatures less than about F. or more than 150 F. are relatively ineffective and temperatures in the range of between about and about F. are preferred in order to obtain maximum coalescence of water at minimum cost. At temperatures below about 95 F. the emulsion becomes difficult to handle because of increased viscosity of bitumen and at temperatures above 120 F. the viscosity of bitumen is so low that it becomes difficult to apply the necessary amount of shearing force to the emulsion.

Recovery of bitumen from coalesced water of the bituminous emulsion may be accomplished in a number of suitable Ways. For instance, the emulsion containing coalesced water may merely be allowed to settle so that water forms a lower layer which may then be removed. This is, however, a rather slow inefficient method of separation and faster techniques are preferred. One preferred method for recovering bitumen from the bituminous emulsion is by contact with a moving inclined surface which causes the bitumen to be removed from the less viscous coalesced water because of preferential adherence of the bitumen to the moving surface. This may be accomplished for instance by means of the apparatus described herein.

With reference to FIG. 1 of the drawing, the dewatering apparatus is shown in schematic form, and includes an endless wide, fiat belt 12, mounted at an acute angle with the horizontal on a lower drive pulley 14 and a second upper pulley 16. The endless belt is constructed of a wide flat preferably elastic material to which bituminous material will adhere and which is generally resistent to deterioration by contact with hydrocarbon materials, water, or sand and impervious to passage of any of these materials therethrough. Any suitable metal to which the hydrocarbon material will adhere or natural or synthetic rubber coated fabric or metal reinforced belt would be suitable for use in the endless movable belt 12 in this apparatus. The endless belt 12 is driven through the lower drive pulley .14 which is mounted on a horizontal drive shaft 18. The horizontal drive shaft 18 is in turn rotatably driven by a suitable power means, not shown, such as an electrical or hydraulic motor either directly coupled to the drive shaft 18 or coupled to the shaft 18 through a suitable transmission, also not shown. The power means rotates the drive pulley 14 in a clockwise direction as shown, and serves to continuously move the endless belt 12 on both the lower and upper pulleys. The upper pulley is rotatably mounted on a fixed hori zontal shaft 20 mounted at a level above the drive shaft 18 and spaced apart from the drive shaft about one half the overall length of the endless belt 12 less one half the total circumference of both of the pulleys. The height of the upper pulley 16 above the drive shaft 18 establishes the angle which the endless belt makes with the horizontal.

A scraper 22 having an edge 23 approxinmately the full width of the flat endless belt is mounted adjacent the belt at a point where the belt rides over the upper pulley 16 and preferably above the horizontal axis of the fixed shaft and acts to remove the hydrocarbon material adhering to the top surface of the belt as the belt passes the scraper 22. The material adhering to the surface of the belt is generally a film of oil which comprises the major portion of the hydrocarbon material contained in the emulsion which has been substantially dewatered by the coalescing and shearing action described hereinafter. The hydrocarbon material removed by the scraper flows down an inclined trough 24 and into a storage tank 26 from which it is removed by withdrawal pipe 28 for further processing.

A horizontally mounted feed tray 32 is located below the fiat endless belt at a point just below the upper pulley 16 and is connected to an emulsion feed pipe 34. Emulsion obtained from a source not shown such as separation vessel which separates bitumen or hydrocarbon material as an emulsion from a slurry of water, sand and bitumen is passed via the feed pipe 34 to the tray 32. The tray has a flat base 36 and upright side and end walls 40 and 38. The fiat base 36 is connected to the top edge of a longitudinally extending fiat plate 44 of slightly greater width than the endless belt 12. The flat plate 44 is adjustably mounted at a spaced distance beneath the belt to obtain a gap 46 which can be varied from about Ms inch to about /2 inch and more preferably between about 7 inch and 4 inch. A pair of plate sidewalls 48 the far one of which only is shown are attached to the side edges of the plate 44 and serve to retain material between the plate and the bottom face 50 of the belt 12. Attached to each bottom corner of the plate are four brackets 52 each having a bolt 54 mounted thereon. A locking nut is used to threadedly attach each bolt 54 to one of four mounting fixtures 56, each having a vertical slot 53 therein through which the bolt 54 ex tends thereby allowing the gap 46 to be changed as required. The mounting fixtures 56 are each attached to elastomeric supports such as helical springs 60, the purpose of which will be explained hereafter.

A vibrator 62 is centrally attached to the bottom of the fiat plate 44 and serves to impart a vibratory motion to the fiat plate 44. The vibrator 62 may be either of the mechanical type, wherein uniform rotary motion is translated to a linear oscillation by rods and cranks or of the internally unbalanced type or it may be an electromagnetically induced type of oscillation, all of which types are well known in the art. The vibration transmitted to the plate is perpendicular to the belt and aids in the shearing and water coalescing actions imparted to the froth by the moving belt 12 acting in concert with the vibrating fiat plate 44 by squeezing the emulsion between the plate 44 and the belt. The helical springs 60, to which are attached the above mentioned mounting fixtures 56 act to isolate the vibrating plate 44 from the fixed support not shown. A low vibrating frequency of from about 100 cycles per minute to about 1,000 cycles per minute is suitable for use in the present dewatering apparatus, the amplitude of the vibration being relatively high. An amplitude corresponding to between about one-fourth and about one-half of the gap 46 between the belt and the plate is preferred. The gap 46 is set between /s and /2 inch and more preferably between W and 4 inch.

A downwardly sloping drain 64 is connected to the bottom edge of the flat plate 44 and acts to remove any non-adhering hydrocarbon material and a major proportion of the coalesced water after the emulsion has been subjected to treatment by the flat plate 44 acting in concert with the moving belt 12. The drain is of any suitable construction and has a top edge 66 of the same width as, and connected to the bottom edge of the flat plate 44. The drains bottom edge 68 is located above a dewatering roller 70 having a width approximately the same size as the belt and the drain 64.

The dewatering roller 70 is a well known device which is used in combination with the other elements of the apparatus e0 effectuate a secondary recovery of the hydrocarbon material from the water released by the action of the belt 12 and fiat plate 44-. The roller 70 is mounted on a horizontal roller drive shaft 72 driven by a rotational drive means which is not shown. The roller is preferably mounted below the bottom edge 68 of the drain 64 in such a position that the material falling from the drain 64 contacts the roller surface at a point from about 10 to about below the apex of the roller 70.

A doctor blade 74 is fixedly mounted adjacent the circumferential face of the roller below the axis of the horizontal shaft 72 driving the roller 70. The doctor blade 74 is inclined at an angle below the horizontal so that adhering hydrocarbon material removed by the blade will drain down the top face of the blade and into a hydrocarbon material receiving tank 75 where the material is temporarily accumulated prior to further processing.

A water tank 76 is located below the dewatering roller 70 at a point directly below the point on the circumferential surface of the roller moving towards and about 90 removed from the apex of the roller, so that water falling from the drain 64 and not adhering to the roller 70 will drain by gravity down the upwardly moving surface of the roller and into the water tank 76.

Finally mounted directly above the top face of the belt 42 is an air sparger 73. The sparger 78 is constructed of a small tube 80 which is transversely mounted above and across the top face of the belt. A plurality of nozzles 82 are attached to the bottom of the tube 80 and are directed at an inclined angle towards the upwardly moving top surface of the belt 12. An air supply 84 of relatively high pressure air is connected to the tube 80 at one end thereof while the other end of the tube is closed by an end cap 86. The jets of air from the nozzles 82 impinge on the oil or hydrocarbon material adhering to the top surface of the moving belt 12 and act to force out any water entrapped by the hydrocarbon material.

In operation a bituminous emulsion containing hydrocarbon material and water is fed through the feed pipe 34 into the feed tray 32 and subsequently introduced by the action of the downwardly moving belt 12 and gravity into the gap 46 between the flat vibrating plate 44 and the moving belt 12. The belt 12 is preferably moving at a linear velocity of between about /2 and 3 feet per second, and the movement of the belt in conjunction with the transverse vibratory motion of the flat plate act to shear the emulsion and coalesce the water entrapped in the hydrocarbon material. The major portion of the coalesced water fiows by gravity down the flat plate 42 and into the drain 64. The material flowing down the drain 64 impinges on the upwardly moving surface of the dewatering roller 70 where the coalesced water falls ofi by gravity and down into the water tank 76. Any hydrocarbon containing material impinging on the surface of the roller 76 adheres to that surface and is carried by the roller to a point adjacent the doctor blade 74 where the adhering hydrocarbon material is removed and drained by gravity into the hydrocarbon material receiving tank 75 for further processing.

The major portion of the hydrocarbon material not drained off the downwardly facing bottom face 50 of the belt 12 is carried around and up the moving inclined surface of the belt when the adhering material, specifically a thin film of hydrocarbon material is first subjected to jets of air from the air sparger 78 which blows out some of the remaining water and then upon passing over the upper pulley 16 is removed by the scraper 22.

A. variation of the emulsion dewatering apparatus of this invention is shown in FIG. 2 of the drawings where like numbers are used to refer to similar elements in the various embodiments of the invention. In this embodiment the fiat plate is located above a moving belt 12a and faces the top moving surface of the belt 12a which is moving downwardly. More specifically the direction of movement of the pulleys and the belt 12a is opposite to that described above in the first embodiment. A fiat plate 44a is adjustably mounted in the same manner as fiat plate 44 opposite the top surface of the downwardly moving belt 12a so as to obtain a gap 46a having similar dimensions to the described above.

A froth feed pipe 340 mounted above the top edge of the first plate 44a feeds froth onto the downwardly moving belt into the gap 46a between the plate 44:: and the belt 12a. A scraper 90 is fixedly mounted adjacent the upper pulley at a point adjacent the bottom of the pulley and serves to remove adhering hydrocarbon material from the face of the belt 12a which hydrocarbon material falls into the storage tank 26a. Similarly a vibrator 62a is fixedly attached to the top of the fiat plate 44a and imparts a vibratory motion to the flat plate, the vibration of the plate being perpendicular to the moving belt 1201.

Similarly secondary recovery of the hydrocarbon material may be obtained by a dewatering roller not shown, horizontally mounted below the lower pulley 14 where the moving belt 12a changes directions so that any material not adhering to the surface of the belt 12a, particularly water impinges on the roller in the same manner as previously described, and further separates any hydrocarbon material from the major portion of water removed at this stage.

Therefore having described the preferred embodiments of my invention, and wishing to cover those changes and modifications which are apparent to those skilled in the art without departing from the spirit and scope of the invention.

1 claim:

1. An apparatus for coalescing water in an aqueous oil emulsion, said apparatus comprising:

a longitudinally extending movable fiat surface, said movable flat surface being mounted at an acute angle with the horizontal, and moving in its own plane but fixed in space with respect to the ground,

a second longitudinally extending flat surface mounted in opposing uniform spaced relationship to said movable fiat surface, both flat surfaces being substantially in parallel to each other, and forming a gap between the opposing fiat surfaces of from about /8 inch to surfaces are parallel, said vibration periodically varying the gap between the opposing flat surfaces and having an amplitude equal to between about A and /2 the gap, said vibration having a frequency of from 100 to about 1,000 cycles per minute, whereby a shearing force is applied to the emulsion thereby coalescing water therefrom which flows out at the lower end of the gap, and

a means for removing adhering oil from the movable flat surface.

2. The apparatus of claim 1 wherein said means for removing the oil adhering to the movable flat surface comprises a scraper mounted adjacent the movable fiat surface.

3. An apparatus for coalescing water in an aqueous oil emulsion comprising:

a pulley rotatably mounted on a horizontal axis,

a second pulley rotatably mounted on a horizontal axis in coextensive spaced relationship and at a lower level than said first pulley,

a continuous endless belt movably mounted on and extending between said first and said second pulleys thereby forming upper and lower runs between said pulleys;

means for moving said belt on said pulleys, said upper run being moved upwardly towards said first pulley and said lower run being moved downwardly from said first pulley towards said second pulley;

a longitudinally extending flat plate mounted in opposing uniform spaced relationship to said belt and extending between said pulleys, said flat plate being substantially parallel with said downwardly moving lower run of said belt and forming a gap between the opposing surfaces of said belt lower run and said plate;

feed means for feeding the emulsion between the opposing surfaces of said belt and said plate,

vibrating means attached to the fiat plate for periodically varying the gap between the fiat plate and belt, said vibrating means vibrating in a direction perpendicular to the plate, horizontally mounted roller, coextensive with said pulleys and mounted below said flat plate at a lower end thereof; a means for rotating said roller; a conduit connected to the lower end of said flat plate and extending to a point above the roller axis where the surface of the roller is moving upwardly, whereby the emulsion is deposited from the fiat plate on the upwardly rotating surface of the roller thereby causing the oil to adhere to the surface of the roller while water rolls 01f into a container; and

doctor blade mounted below the roller axis adjacent said roller surface for removing the oil from the surface of the roller, said oil falling into a second container.

4. The apparatus of claim 3 wherein said means for moving said belt on said pulleys, moves said belt at a linear speed of from about /2 to about 3 feet per second.

5. Apparatus for coalescing water in an aqueous oil emulsion comprising:

a pulley rotatably mounted on a horizontal axis,

a second pulley rotatably mounted on a horizontal axis in coextensive spaced relationship to and at a lower level than said first pulley,

a continuous endless belt movably mounted on and extending between said first and said second pulleys thereby forming upper and lower runs between said pulleys;

means for moving said belt on said pulleys, said upper run being moved upwardly towards said first pulley and said lower run being moved downwardly from said first pulley towards said second pulley;

a longitudinally extending flat plate mounted in opposing uniform spaced relationship to said lower run of said belt extending between said pulleys, said flat plate being substantially parallel with said belt and forming a gap between the opposing surfaces of said belt lower run and said plate,

feed means for feeding the emulsion between the opposing surfaces of said belt lower run and said plate,

vibrating means attached to the fiat plate for periodically varying the gap between the flat plate and said belt lower runs,

an air sparger mounted above the upwardly moving upper run of the belt and between the first and second pulleys, said air sparger directing a stream of air at the top face of the belt upper run to force water out of the emulsion,

a means for supplying air to the air sparger, and separate means at the bottom of the second pulley for collecting water and oil respectively.

6. The apparatus of claim 5 wherein the separate means for removing water and oil from the belt comprise a scraper mounted adjacent the second pulley and opposite the face of the belt where the second pulley and the belt are moving downwardly whereby said scraper removes hydrocarbon material adhering to the face of the belt, the Water having rolled 011 into a water collecting basin.

References Cited UNITED STATES PATENTS Pratt 208-187 Shaw 210-19 Ketchum 210-389 5 WILBUR L. BASCOMB, ]R., Primary Examiner J. SOFER, Assistant Examiner US. Cl. X.R.

Wehmiller et a1. 210-19 10 252-349; 208-11; 196-46 

